This disclosure relates to stopping the waste of water while waiting for hot water to arrive at remote faucets after the faucet has been opened. Many engineers and water technicians have determined that the average American home wastes about 10,000 to 15,000 gallons of water annually while running cooled water down the drain before hot water arrives at the sink. The wait time required varies based upon the length and diameter of the distribution pipe from the heater to the sink. In many homes the wait can be three minutes or more, during which time six or more gallons of potable water are wasted. FIG. 1 shows measured data relating how the wait time for a conventional system is essentially eliminated in a hot water system after installation of convective hot water circulation.
Test data in FIG. 2 show that water in a ½-inch diameter copper pipe in a 70° F. ambient environment will cool from 120° to 90° in 30 minutes; thus, the potential for 20 to 30, or more, wait and waste cycles per day exists in the home with multiple plumbing branches and outlets. Water at 90° F. is not considered warm enough for personal use.
This waste of water can no longer be tolerated in our society, as water shortages already exist across the country, and water departments have implemented many user conditions restrictions due to drought. The United States government initiated a water conservation program in 1994 with the introduction of low flow toilets and shower heads that have proven to be very unpopular with the public, and are often disabled. Rapid hot water circulation is the only residential water conservation system that people will gladly use if it can be easily installed and available at a reasonable cost. Systems using electrically driven pumps have been available for several years however their complexity and extremely high cost plus the requirement for professional installation have significantly limited their acceptance. They also require electrical power outlets not normally available in appropriate locations resulting in additional cost.
Convective circulation is a natural process responding to the laws of physics. The system is simple in design, yet sophisticated in concept. It is extremely reliable and operated by gravity, which has never failed. This system design can easily be installed by most homeowners, and needs no power or gas. The present disclosure is an improvement over the convective circulation system disclosed in U.S. Pat. No. 5,331,996, which it is estimated that almost 28,000 of its system have saved three billion gallons of water since 1996, and are currently saving 270 million gallons per year for homeowners happy with almost instant hot water. The simplicity of this disclosure results in a significant reduction in cost to procure and install.